G3/3 — Left a lambda probe in front of the catalytic converter G3/3x1 — the Socket left a lambda probe (in front of the catalytic converter) G3/4 — Right a lambda probe in front of the catalytic converter G3/4x1 — the Socket right a lambda probe (in front of the catalytic converter) G3/5 — Left a lambda probe behind the catalytic converter G3/5x1 — the Socket left a lambda probe (behind the catalytic converter) G3/6 — Right a lambda probe behind the catalytic converter G3/6x1 — the Socket right a lambda probe (behind the catalytic converter)